Injuries kept Giants rookie safety Darian Thompson from holding onto his starting spot, and now they will prevent him from playing again this season.

Thompson, the Giants’ third-round pick out of Boise State, was placed on injured reserve Wednesday. He will undergo surgery to repair a foot injury that has sidelined him since Sept. 18, the team announced.

Thompson, 23, won the starting free safety job out of training camp, but a shoulder injury kept him out of the Giants’ final two preseason games and limited his playing time in the season opener against the Cowboys. He started against the Saints in Week 2 before sustaining the foot injury that forced him to miss five more weeks and ultimately ended his season.

The Giants signed offensive lineman Adam Gettis off the practice squad to fill Thompson’s roster spot. Gettis, primarily a practice-squad player over his five-year career, joins the Giants as a plug-in replacement for left guard Justin Pugh, who is expected to miss 3-4 weeks with a sprained MCL.